The invention relates to molding apparatus, and especially for molding two articles simultaneously.
When molding epoxy resin material around a semiconductor chip and a substrate, it has become common practice to perform the molding operation simultaneously on two separate substrates which are located side by side within a mold. Commonly, a number of semiconductor chips are attached to one strip of a substrate and it has become common practice to mold two substrate strips simultaneously in the same mold in order to increase the speed and efficiency of the molding operation.
During the molding operation, the substrate strips are usually clamped between the mold halves. One of the problems with this system is how to compensate for variations in thickness between the two substrate strips to ensure that both substrate strips are clamped between the mold halves with the necessary clamping force.
In accordance with a first aspect of the present invention, there is provided molding apparatus for simultaneously molding a molding material around a number of separate substrates, each substrate having a semiconductor chip mounted thereon, the apparatus comprising a mold housing adapted to have mounted thereon a mold half comprising two mold cavity members, the mold housing comprising a first mold cavity member holding section and a second mold cavity member holding section, the first and second holding sections comprising a common support surface, the support surface including a first movable member in the first holding section and a second movable member in the second holding section, the first and second movable members being movable between a first position in which they protrude out of the support surface and a second position in which they protrude less from the support surface than in the first position, a first drive mechanism coupled to the first movable member and a second drive mechanism coupled to the second movable member, the first and second drive mechanisms being independently actuatable to move the first and second movable members between the first and second positions.
Preferably, the first and second drive mechanisms comprise a linearly movable member coupled to the respective movable member.
Preferably, the linearly movable member is coupled to the respective movable member by a rotatable member which is rotatable with respect to the linear movable member and the respective movable member. Typically, the linearly movable member is movable substantially perpendicularly to the direction of movement of the respective movable member.
Preferably, the first and second movable members are movable in a direction substantially perpendicular to the base surface.
In accordance with a second aspect of the present invention, there is provided a mold half comprising a support member, two mold cavity members movably mounted on the support member for movement relative to the support direction in a first direction, a mold cavity housing being movably mounted on the support member for movement relative to the support member in a direction substantially parallel to the first direction, and biasing means mounted between the mold cavity housing and the support member to bias the mold cavity housing away from the support member.
Preferably, the mold half further comprises a first mold cavity actuator coupled to the first mold cavity member and a second mold cavity actuator coupled to the second mold cavity member, movement of the actuators moving the respective mold cavity member in the first direction.
Typically, the first and second mold cavity actuators extend through the support member.
In accordance with a third aspect of the present invention, there is provided molding apparatus for simultaneously molding a molding material around a number of separate substrates, each substrate having a semiconductor chip mounted thereon, the apparatus comprising a mold housing having a mold half according to claim 6 mounted thereon, the mold housing comprising a first mold cavity member holding section, in which the first mold cavity member is located, and a second mold cavity member holding section, in which the second mold cavity member is located, the first and second holding sections comprising a common support surface on which the support member is located, the support surface including a first movable member in the first holding section and a second movable member in the second holding section, the first and second movable members being coupled to the respective mold cavity member, movement of the first and second movable members moving the respective mold cavity member in the first direction, a first drive mechanism coupled to the first movable member and a second drive mechanism coupled to the second movable member, the first and second drive mechanisms being independently actuatable to move the first and second movable members between the first and second positions.